The current proposal seeks preliminary data toward understanding the cognitive and neuroanatomical basis of the decline in working memory performance observed in older adults using functional MRI. This work will contribute to the field of aging research in several important ways. First, it will provide basic data regarding the most common and debilitating symptom of aging. Second, these studies apply the latest technique of functional neuroimaging, event-related fMRI, to identify specifically which regions and which cognitive processes are affected by aging. As yet few attempts have been made to understand the underlying neural mediators of the well-documented age-related decline in working memory (WM). In 3 sets of studies I plan to test three hypotheses. Hypothesis 1 is that age-related decline in WM performance is associated with age-related decline in dorsal, but not ventral, prefrontal cortical activity. The observation in prior studies of age-equivalent ventral PFC activity is consistent Hypothesis 2 that older adults may rely on compensatory mechanisms to maintain performance on some WM tasks. I seek evidence for a neural compensation mechanism using criteria developed from results of prior research. Behavioral research has tied WM decline to processing speed reductions, but no attempts have yet been made to understand the neural mediators of age-related changes in processing speed on WM tasks. Hypothesis 3 is that relationships between age and processing speed on WM tasks will determine individual differences in neural activity, mainly in dorsolateral PFC relative to other cortical regions. To test these hypotheses I will orthogonally and parametrically vary maintenance and manipulation demands in separate verbal and object WM tasks. These studies constitute the starting point for a program of research aimed at understanding the precise neural architecture of cognitive aging. It will eventually inform a basic understanding of the functional neuroanatomy of the brain, how it changes with age, and how therapeutic techniques may be applied to age-related cognitive disorders such as Alzheimer' s disease.